1. Field of the Invention
The present invention relates to an enamel coating for the bottom of a cooking utensil such as a frying pan, saucepan, shallow casserole or the like.
The invention is also directed to cooking utensils provided with an enamel coating of this type.
2. Description of the Prior Art
As disclosed in French patent No 2,544,338 in the name of the present Applicant, a known coating for the bottom of cooking utensils comprises a first enamel layer which completely covers the bottom of the utensil. On this layer is formed a second non-continuous layer of enamel constituting a decorative surface which is applied by screen process after drying of the first enamel layer. These two layers are obtained from an enamel frit and are fired simultaneously.
Simultaneous firing of the two enamel layers makes it possible to obtain exceptional adherence of the two layers and excellent resistance of these latter to the severe thermal shocks to which the enamel coating is exposed.
The non-continuous outer layer which constitutes a decoration makes it possible not only to improve the appearance of the bottom of the utensil but also constitutes a wearing layer which protects the underlying enamel layer against impacts and scoring. In fact, the raised surface of this decorative layer is capable of wearing without excessively impairing the attractive appearance of the enamel coating.
Nevertheless, by reason of the non-continuous character of said outer enamel layer, this layer wears too rapidly, especially when this enamel is obtained from an enamel frit for aluminum which is of distinctly lower hardness than enamels for utensils of steel or of cast-iron.
In order to provide a remedy for this relatively low hardness and to increase the resistance to wear of the outer enamel layer having a raised surface, the present Applicant has proposed in his French patent No. 2,544,338 to fill this enamel layer with hard particles having angular shapes such as alumina, silicon carbide and the like, some of which project from the surface of the enamel layer.
However, these hard and angular particles which project from the surface of the enamel considerably increase the coefficient of friction of this surface which is consequently difficult to clean. Furthermore, as they become worn, the particles give the raised-surface enamel decoration an unattractive appearance.
Moreover, by virtue of its insulating properties, the enamel coating affects the transmission of heat through the bottom of the cooking utensil.
The aim of the present invention is to overcome these disadvantages of the aforementioned enamel coating.